My group had one ... briefly.
Human Rogue
Human Wizard
Elf Cleric
Dwarf Fighter
I played the Cleric. The DM assassinated my PC around level 4, and a local Druid reincarnated me as a Bugbear. This annoyed me (because I was the only one with a positive Charisma bonus), and annoyed the DM (because he decided that I was now way too strong, when I decided to start taking advantege of my Bugbear strengths).
The Wizard player disappeared, and now I'm making a Human Anima Mage to journey with the party.
In the game that I DM, we have three Humans: a Wizard / Loremaster, a Wizard / Ranger / EKnight, a Monk / Paladin / PrC, and sometimes a Ranger. There's also a cohort (Warforged Fighter / Exotic Weapon Master / Occult Slayer), and the EKnight sometimes gets a squad of mid-level Luxorian Regulars (Army NPCs). They are frequently accompanied by a couple of wyrmlings, whose eggs they liberated in an earlier adventure. (Yes, at some point soon, the wyrmlings will ask "are you my mommy?"... and the wyrmlings have good Sense Motive checks, of course.)
Anyway. Not much balance. But fun seems to occur even without it.
-- N